Seasonal affective disorder
Seasonal affective disorder is the 'with seasonal pattern' specifier applied to major depressive disorder or to bipolar 1 or 2 disorder, with episodes recurring in autumn or winter and remitting by spring for at least 2 consecutive years. Diagnosis is clinical, using standard mood-episode criteria plus the seasonal timing. First-line treatment is daily phototherapy, 10,000 lux for 30 to 60 minutes each morning, combined with a second-generation antidepressant such as bupropion XL.
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What this article covers
- Overview
Definition: seasonal affective disorder is not a standalone diagnosis but the "with seasonal pattern" specifier applied to major depressive disorder (MDD) or to bipolar 1 or 2 disorder, in which mood…
- Epidemiology
Sex distribution: seasonal affective disorder is twice as common in women as in men.
- Risk factors
Female sex: women are affected about twice as often as men.
- Pathophysiology
Light-dependent circadian pathway: environmental light governs suprachiasmatic nucleus activity, norepinephrine release from the superior cervical ganglion, and melatonin secretion from the pineal…
- Clinical features
Underlying mood episode, the required foundation: the patient must meet criteria for a major depressive episode, or for mania or hypomania, before the seasonal specifier can be applied.
- Differential diagnosis
Major depressive disorder without a seasonal pattern: depressive episodes occur without a consistent autumn or winter onset and spring remission, and seasonal episodes do not outnumber nonseasonal ones.
- Diagnosis
The diagnosis is clinical: it is confirmed when a patient meets full criteria for a major depressive, manic, or hypomanic episode and the episodes show a temporal relationship to a particular season…
- Management
First, assess safety: if suicidal or homicidal ideation is present, hospitalize; for acute agitation, give lorazepam 1-2 mg IM or IV, may repeat, while arranging psychiatric evaluation.
- Complications
Suicide: depression is a major risk factor for suicide, and every episode requires a specific suicide risk assessment regardless of the seasonal label.
- Prognosis
Good response to combined treatment: phototherapy plus CBT or a second-generation antidepressant is an effective plan for the seasonal depressive episode.
- Prevention
Screen all adults for depression: use the two-question screen at routine visits; a positive response should prompt further evaluation with the PHQ-9.
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